The invention relates to a device for quickly exchanging guide rollers or guide roller sets on and off supporting shafts of a roll mill train.
In the cold alignment of profiles on roller aligning machines, it is always desirable to exchange the guide rollers in as short a time period as possible. When preparing the roll mill train for a new profile, the rebuilding period of the aligning machine should under no circumstances exceed the time required for the operation of the roll mill train itself. Depending upon its design, a roller aligning machine is provided with between 7 and 11 supporting shafts. The guide rollers of each shaft are assembled by means of a flange bushing and locking nut to make up a roller set. A key spring connection serves as torsion safeguard between the shaft and flange bushing. To rearrange the roller aligning machine with a new profile, all roller sets must be withdrawn from their respective shafts and replaced with new roller sets.
It is well known in the art to exchange the guide roller sets by means of a crane with the assistance of wire cables, pliers or similar devices. Due to the very high hoisting speed of rolling mill hangar cranes, cranes with extremely low hoisting speeds are used, which are specially installed for the purpose of changing guide rollers at the roller aligning machines. However, despite the favorable operating features of such cranes, the alignment of a roller set with the central axis of the supporting shaft to facilitate slipping the set onto the shaft is very time-consuming. This is especially true in view of the fact that the clearance between the supporting shaft and the flange bushing is in the order of a few tenths of a millimeter, and a roller set may weigh up to 7 tons.
It is also known to utilize rail as well as freetraveling devices equipped with several horizontally disposed mandrels arranged opposite the supporting shafts. A mandrel of this device must be brought before a supporting shaft in exact alignment if a roller set is to be slipped from the supporting shaft onto the mandrel or vice versa. Due to the narrow clearances, this, too, is a very time-consuming procedure. Furthermore, the devices mentioned require a great deal of floor space and are expensive. Accordingly, their use is generally limited to new plants since there is usually not enought space in existing plants to include an additional roller exchange device.
It is a primary objective of the present invention to provide a device of the crane type to quickly and easily exchange guide rollers in a roll mill train. The apparatus disclosed herein may be installed in already existing plants with a minimum space requirement. Generally, the present invention is characterized by a centering sleeve-like member mounted on a free frontal face of the support shaft and arranged and configured whereby the upper surface thereof for about 45.degree. on either side of the center vertical is an aligned continuation of the support shaft shell surface. The remaining surfaces of the member converge radially inwardly from the imaginary projection of the shaft shell surface. In this manner, the axial spread of the member approximately matches the breadth of the guide roller or guide roller set. The guide roller set may be easily slipped onto the centering sleeve by any hangar crane. Since the outer dimension of the sleeve member is reduced relative to the support shaft, it is not necessary to suspend the roller set from the crane either exactly horizontal or exactly aligned with the support shaft. After slipping the roller set onto the centering sleeve, the set is in exact alignment with the support shaft and can be easily pushed onto the latter. The time-consuming alignment of the roller set with the support shaft is thus eliminated.
In accordance with another feature of the invention, the sleeve member may be equipped with a key spring aligned with the key spring of the support shaft. The key spring of the guide member is formed to be of a width equal to the key spring of the support shaft and includes lateral faces which converge in the radial direction. When mounting the guide rollers or the guide roller set, the conicity of the sleeve key spring provides sufficient clearance to slip the roller set easily onto the support shaft.
Slipping the roller set onto the support shaft or, in reverse, the withdrawal of the set from the support, may be done in a variety of ways. For example, light roller sets may be changed by hand, while heavier ones can be lifted by means of hydraulic or mechanical devices incorporated in the aligning machine, or by the crane itself.